Book Review

Synopsis:
An examination of how Adam and Eve can be a true model of human origins.Summary: Science and Human Origins examines the scientific basis for neo-Darwinian evolution, finding mutation and natural selection to be "Darwin's little engine that couldn't." In addition, the book examines the gaps in the hominin fossil record, "junk DNA," and the assertion that there is too much genetic diversity for humanity to have arisen from two initial parents.

Rating:

Rich Deem

Introduction

Science and Human Origins
is the recent book by the Discovery Institute on human origins. Although the
Discovery Institute tends to stick to intelligent design without defining the
Designer, this offering seems to be aimed specifically at Christians. In fact,
the final chapter is entitled, "The Science of Adam and Eve." Is Discovery
siding with the creationists or just attempting to market to a larger audience?

John G. West, Associate Director of the Center for Science and Culture
introduces the topic by defining terms and the general theory behind common
descent and natural selection, along with an introduction of the topics in
the book.

Science and human origins

Ann Gauger takes the first chapter, which looks at common descent from
the perspective of human origins. Gauger discusses the things that make
humanity unique among all other species of life, asking whether such changes
were possible in the six million years posited as the timeframe in which
humans diverged from apes.

Darwin's little engine that couldn't

Douglas Axe discusses the plausibility of mutation and natural selection
accounting for all evolutionary change. Axe and Gauger had performed
mutation experiments in order to determine whether mutation could change
structurally similar (but functionally different) enzymes into one another.
The publication of these experiments cause a lot of controversy, with
evolutionists claiming that the results didn't discredit mutation and
natural selection as the driving force of evolution. Axe and Gauger
attempted to take structurally-related enzymes and produce the function of
one from the other through mutation. In the past, creationists have been
blasted for showing calculations about how unlikely it would be to produce a
given protein from scratch. Since evolutionists don't believe that proteins
evolved from scratch (other than the first, putatively simple ones), the calculation
is said to be bogus. In theory, similarly functioning proteins could arise, even though
the actual amino acid sequences of those proteins could be quite different (although, in
practice, this is usually not the case). Axe and Gauger found that
even though the two proteins looked the same, the second protein's function
could not be coaxed from the first through mutation. Calculations showed
that a minimum of seven discrete mutations were required to change the
function, something that mutation seemed unable to accomplish. Hence, Axe
and Gauger concluded that the putative driving force of evolution (mutation
and natural selection) was "Darwin's little engine that couldn't."

Human origins and the fossil record

Casey Luskin wrote chapter 3 on human origins and the fossil record. This
chapter examines the fossil record of hominins. Luskin reports that the
fossil record is, for the most part, sporadic and fragmented, with many
early species classified on the basis of a handful of bones. Some of the
skeletons required extensive reconstruction from having been crushed, which
makes the claims of bipedalism questionable. Luskin also reports on the
brain capacities of hominin species, showing that there were definite
discontinuities in sizes across the spectrum of hominin species. The figure
right (not from the book) shows more recent data from a meta-analysis of all
hominin fossils discovered to date. The data shows three distinct groups of
species—the Australopithecines, early Homo, and later
Homo species. In fact, all four later Homo species have
significantly larger brain capacities compared to their nearest "relative,"
with p values ranging from <0.05 to <0.001 (data from Supplementary
Material, Shultz, Nelson, and Dunbar, 2012).1

Luskin concludes that all
hominin species before Homo erectus were apes and not part of the
human line. In essence, Luskin concludes that Adam was a Homo erectus
and that Neanderthals were all part of modern humanity. However, what Luskin
didn't mention was that no Neanderthal mtDNA has survived in modern humans (implying
that human males never mated with Neanderthal females or that the offspring
of such matings never survived to reproduce) and that evidence of
Neanderthal/human mating contributed almost nothing to the modern human
genome, and, in fact, did not occur at all in some human
populations (such as Africans). Since we don't have any surviving DNA from
Homo erectus we cannot determine the genetic relationship between
that species and modern Homo sapiens sapiens. However, since there
is no evidence of religious artifacts among Homo erectus remains, I
would suggest that Adam and Eve were not Homo erectus.

Junk DNA

Luskin examines the evolutionists' claim that "junk DNA" conclusively
shows that life evolved through trial and error, with most of eukaryotic DNA
consisting of the DNA that has no function. Recent studies show that a large
percentage of "junk" or "non-coding" DNA actually codes for a plethora of
RNA transcripts (although many of these transcripts do not get encoded into
proteins). Most of this RNA is involved in regulation of gene expression, a
role vital for the proper functioning of protein-encoding genes. In
addition, the structural integrity of chromosomes require the existence of
large amounts of repeating sequences that bind to the histone proteins that
hold the chromosomes together. However, in bacteria, whose DNA is not
contained within chromosomes, have very little "junk DNA," demonstrating
that evolution does not produce non-coding DNA for no reason. Luskin ends
the chapter with an examination of the putative chromosome 2 fusion event
that supposedly took place during the evolution of humanity's ancestors.
This section has caused a huge amount of controversy with the evolutionists
claiming foul in online blogs about the reporting of the data. The chromosome 2 fusion claim
has been an evolutionary mainstay for years, although recent evidence shows
that it is not quite as neat and tidy as the evolutionists had originally
claimed. It was interesting following the online banter as evolutionary
biologists originally attempted to refute the claims, but later just tried to explain
how the messy details actually fit with what would have been expected to
have been produced through evolutionary mechanisms (maybe not originally,
but now that the data is more clear).

The science of Adam and Eve

In a rather shocking deviation from their usual strategy of sticking
solely to "intelligent design," Ann Gauger's final chapter deals directly
with the Bible's claim that humanity arose from two original parents, Adam
and Eve. Studies by population biologist Francisco Ayala and others had
originally shown that genes of the human major histocompatibility complex
(MHC) had arisen from at least 32 different alleles, requiring an effective
population size of 100,000 and a minimum size of 4,000. The problem with the
analysis is that the assumptions required by the population model were not
met by the MHC genes studied. In order for the mathematical model to work,
the genetic sequences in question must not be susceptible to natural
selection and have a constant background mutation rate. However, the MHC
genes are involved in host defense, so that the more diversity the genes
express, the better likelihood individuals will be able to respond to
infectious disease. So, the reason why the genes exhibit such a large
diversity of alleles is because it is beneficial for populations to express
maximal diversity of response to disease. However, what Gauger does not
mention is that since Ayala's first analysis of human population sizes in
the 1990's, many other studies have been done, most of which have not
used MHC genes.2 Even so, from the original data suggesting an effective
population size of 100,000, the numbers have fallen considerably, and now
stand between 3,000 and 10,000. However, the number has never been as low as 2.

Conclusions

Science and Human Origins is a
lay-level examination of what science has to say about human origins. A
significant amount of the book is also devoted to critiquing the basis for
Darwinian evolution. Although the book does not go into the details of the
science behind evolutionary theory, it does contain extensive citations of the
scientific literature for those who are interested in those details. The book is
short and easy to read, even for those who have minimal background in biology.
The one thing I didn't like about the book was the overly-zealous attacks on
fellow Christian Francis Collins (who believes in theistic evolution), mostly by
Casey Luskin.

In a surprise move, the Discovery Institute now seems to be headed toward
creationism, which they had previously said was not part of their
intelligent design focus. In fact, the book has minimal information on the
intelligent design of humans, which makes them unique among all other
hominids, although there is much that could have been written on this topic.
Still, the book contains a good critique of Darwinian evolution.